Currently in the 3rd Generation Partner Project (3GPP), a feature of dynamic Time Division Duplex (TDD) reconfiguration has been introduced in Long Term Evolution (LTE) system. That is, the TDD configuration in a cell is not fixed but may vary depending on actual traffic requirement. For example, if more traffic is required in the Downlink (DL), more subframes can be allocated to the DL. On the other hand, if more traffic is required in the Uplink (UL), more subframes can be allocated to the UL. Although the dynamic TDD reconfiguration is suitable to meet traffic requirements, it may be problematic for a Transport Control Protocol (TCP) transmission since it takes time to switch the TDD configuration at both a base station (e.g., evolved Node B (eNB)) and a User Equipment (UE), especially for their hardware components. If one of the base station and UE has finished the TDD reconfiguration while the other has not, there may be useless and thus unnecessary transmission of TCP packets, resulting in a waste of power which is vital especially for the UE.
Furthermore, if such TDD reconfiguration time is comparable with the TCP round trip time, the performance of the TCP transmission may be significantly degraded as the base station and UE cannot transmit or receive data successfully during the TDD reconfiguration time and a corresponding packet loss ratio will thus be very high. In particular, due to packet loss or delayed acknowledgement caused by the TDD reconfiguration, a timeout timer at the TCP sender may expire. In this case, with a congestion control mechanism according to the TCP protocol, a congestion window at the TCP sender will be reduced to 1 and the recovery of the TCP transmission will be very slow after the TDD reconfiguration due to e.g., the so called “slow start” mechanism.